Lifting oil from the bottom of a wellbore to the surface of the earth is sometime more costly than the profit derived from the crude, and therefore, on marginal wells, an improvement in efficiency often spells the difference between abandonment of valuable crude oil as contrasted to continued production of the well. In deep wells where the reservior no longer has sufficient bottom hole pressure to free-flow the well, it is common to use a bottom hole hydraulically actuated reciprocating pump assembly as evidenced by my U.S. Pat. Nos. 3,517,741; 3,650,640; 3,453,963; 3,957,400; and 3,865,516. As the production formation of a well continues to be depleted, and the lifting force required to bring the oil to the surface of the ground continues to increase, additional energy must be expended by the engine of the pump assembly, or alternatively, the size of the pump piston must be decreased in order that sufficient lifting force be available for pumping the crude from the pay zone up to the surface of the earth.
It is therefore desirable to be able to use a relatively large downhole pump assembly for lifting a relatively large volume of crude by augmenting the action of the downhole pump so as to boost the pump action. Otherwise, increased hydraulic pressure must be resorted to in order to achieve the greater lifting force, and ultimately the greater forces exerted on the engine and pump assembly will rapidly deteriorate the entire apparatus so that it wears out early in its life.
It would be therefore be desirable to incorporate such a jet boosting action in any number of different downhole reciprocating-type pumps, as for example, one of the above mentioned prior art Roeder pumps.